From 9a1dc3891255afd836f355b117fd6b975d0b1eb2 Mon Sep 17 00:00:00 2001 From: Shawn Lin Date: Mon, 14 Nov 2016 15:21:14 -0600 Subject: of/pci: Add of_pci_get_max_link_speed() to parse max-link-speed from DT This new helper function could be used by host drivers to get the limitaion of max link speed provided by DT. If the property isn't assigned or is invalid, it will return -EINVAL to the caller. Signed-off-by: Shawn Lin Signed-off-by: Bjorn Helgaas Acked-by: Rob Herring --- drivers/of/of_pci.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers/of') diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c index b58be12ab277..0ee42c3e66a1 100644 --- a/drivers/of/of_pci.c +++ b/drivers/of/of_pci.c @@ -119,6 +119,27 @@ int of_get_pci_domain_nr(struct device_node *node) } EXPORT_SYMBOL_GPL(of_get_pci_domain_nr); +/** + * This function will try to find the limitation of link speed by finding + * a property called "max-link-speed" of the given device node. + * + * @node: device tree node with the max link speed information + * + * Returns the associated max link speed from DT, or a negative value if the + * required property is not found or is invalid. + */ +int of_pci_get_max_link_speed(struct device_node *node) +{ + u32 max_link_speed; + + if (of_property_read_u32(node, "max-link-speed", &max_link_speed) || + max_link_speed > 4) + return -EINVAL; + + return max_link_speed; +} +EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed); + /** * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only * is present and valid -- cgit v1.2.3